Telephone system



July 14; 1925. I 1,546,113

W. P. ALBERT TELEPHONE SYSTEM Fi ed Aug. 27, 1925 2 Sheets-Sheet 1 //7 ve/vfor: Wei/fer A/ber/ July 14,1925. 1,546,113

W. P. ALBERT TELEPHONE SYSTEM 2 Sheets-Sheet 2 Ww/e/ PA/be/f.

by WA)? Patented July 14, 1925.

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"trnLEPnoNn SYSTEM.

Application filedAugust $31923. Serial No. 659,515.

T 0 all whom z'twmy-conbemr- 1 Be it known that I, l/VALTER P. ALBERLL-,,ZL citizen of the United States of America, residing at East Orange, in the county-bf EsseX, State of New Jersey, have invented certain new and useful Improvements in Telephone Systems, of whichthe following is a full,; clear, concise, and exact description. Y J

This invention relates to telephone sys tems and particularly to machine switching systems of small capacitysuch as those used in private branch exchange installations.-

- The object ot-the inventiontis to secure-the maximum efiiciencyfrom; small rotary switches and toproduce asmall capacity systemwhich will be; simple, and easily maintained. ;m f A feature of the invention-residesinthe useot a circuit arran ement in combination iwith a simple rotaryswitch whereby allot the active terminalsmaybe used-tor line .connection. Y i J v Another feature" resides inthe provision ot'a link circuit for extending connections comprising a switch and means responsive to'a plurality of trains ,ot-in'ipulses tor-setting said switchythe switch itself being directly responsive to but a single one of said trains of impulses. e l. Heretotore similar systems have employed certainoit the active contacts as switching positions and the switch was first directively set on such contacts before being moved to connection with the wantedterminals; In the present arrangement. greater 'efliciency is obtained by utilizing such contacts for line numbers and. the wear andfltear onthe apparatus is at ,the same timereduced by carrying on such necessary switching 0pleft-hand armature and back cont act of. re-

lay 200, oft normal contact 109', back contact e'rations by auxiliary and more-easily maintained apparatus.

. The drawings when placed Fig. 2;to the right of Fig. 1 diagrammatically illustrate a circuit arrangment embodying this=invention. Fig. 1 represents acalling line and a finder switclr together with an allotter switch for preselecting an-idle finder. Fig.

2 represents a connector switchgand all of its associated relays together with two called lines."

The finder switch comprises a small stepby-step switch having SlX brushes and six corresponding rows of terminals.. Since'it own circuit.

requires but three brusl es to-take careot the 'connections to a linefthe finder switch 1s divided into two sections, ot three brushes each leading to twoggroups of lines.

The

substation 100 is shown. as connecteclto-the I terminals of the first group of lines, such connection beingindicated through the group having a conductor leading to the "allot-terbrush A .-.VVlren the 'subscriber at? station 100 'removes his receiver from 'its switchhook a circult is established over the loop oi thecalling-substation and-through the windings of line relay 103- causing this. relay to attract .1tsia r1natures. 2 Through its left-hand arinature, relay .103 causes the en'ergiz'ation of group relay 102-and through its-right-hand armature and resistance 104a places alow resistance battery potential on the sleeve conductor of thecalling line. -The energizati'on of relay 102 results in the-establishment 0tv a circuit from ground, right-hand armature and front, contact of relay 102, brush ,A

' which is restingon. the terminal corresponding to an. idle line finder, the armature and back contact ot' relay 105, armature 106 and I back contact otrelay 107, back contact and armature of stepping magnet; 108, winding of magnet 108 to battery and ground. Mag' net 108 becomes energizedin thisci-reuit and vattracts its armature" thereby breaking its Upon its deenergization mag-- net 108 moves the brushes shown in a vertical gline beneath it to their first active contacts. .UPOH such movementof the brushes the" ottno'rmal contact109is closed, whereupon a circuit. is established" from ground,,inner and armature of magnet 108, winding of inbetore described. for the I energization of magnet 108 and being provided for thepur pose of rotating the brushes back-to their normal position should the call. be abandoned before" the callingline is reached bythe finder switch. Under normal. conditions, magnet. 108, being in a selt-interriipting circuit, will cause the brushesq'ot the finder switch to move-step-by-stepuntil, the calling I line is reached, whereupon a. circuit will be established from ground, right-hand armature and front contact of relay 102, brush A winding of relay 105, brush FS, resis tance 10.4., iront onta t an ig th ad;

arma ur of. line r lay 1 to b tte y nd ground whereupon relay 105 becomes energized. The energization of relay 10 extends the ground at its armature through its front contact to the winding of relay so' that the calling subscribers line is now ex tended to the windings of line relay 201 and front contact of relay 200, armature 110 of relay 107, winding of relay 107' to battery and ground. A circuit is also established from ground, the inner left-hand armature and front contact of relay 200, armature 111 of relay 107, brush, FS, windingfof cut-off relay 112 to battery and ground. It-will be noted that the cutvoif relayis marginal and that while ground was extended through the winding of relay 105, it did not become operated, but that when a direct connection from ground was placed on the sleeve conductor of the line,'the cut-off relay became energized. A direct ground placed on the brush FS is also extended to the other terminal of relay 105 so that. this relay now becomes shunted and consequently deenergizes. At this time a ground is also extended from the inner left-hand armature and front contact of relay 200, brush A armature and back contact of magnet 113, winding of magnet 113' to battery and ground, whereupon this ma et becomes energized and moves the brus es A A and Aforward. As long as grounded connections are found on the terminals traversed by brush A mag-net 113 will continue to step such brushes, but when an idle finder switch is reached, magnet 113 ceases its operations. The energization of the cut-off relay 112 causes thedeenergization of line relay 103 and the consequent deenergization of the group relay 102, so that the connection is now in a-stable condition awaiting the sending of impulses from the calling substation.

According to the scheme employedin the connector switch there are four groups of lines numbered respectively 10 to 49. This switch, like the finder switch, is a simple rctary type switch having six brushes which are divided into two sets of three each. The

first set of brushes has access to lines 10 to 29 and'the second set of brushes has access to lines 30 to 49, inclusive. There is a prirnary normal position on which all brushes lines 30 to 39. Between the secondary normal position and primary normal position, the first set of brushes reaches lines 20 to 29 and the second set of brushes reaches lines 40 to 49. Thus when the first digit is 1, the firstset of counting relays 208 and. 209 will be energized with the result that the switch remains in its normal position and the first set of brushes is rendered effective. 1 The digit 1 is represented by a single short interruption of the calling line circuit which results in the momentary deenergization of relay 201, whereupon a circuit is extended from ground, the armature and back contact of relay 201, the front contact and right-hand armature of holding relay 202, winding of slow releasing relay" 203,

inner left-hand armature and back contact of relay 204', outer left-hand armature and back contacts of relays 205, 206, 207 and 208, winding of relay 209 to battery and ground; Relays 203 and 209 become energized inthis circuit and establish a, connection Jfromj ground, the alternate contact and right-hand armature of relay 203, back contact and outer left-hand armature of relay 20?, armature and front contact of relay 209, winding of relay 208i, winding of relay 209 to battery and ground. Relay 208 is, however, short-circuited at this time so that it does not become energized until relay 201 again attracts its armature. When this happens the round extended over the armature and back contact of relay 208 is removed and relay 208 becomes energized and relay 209 remains energized in the circuit last traced.

Another circuit is also extended from ground, the outer right-hand armature and front contact of relay 200, the alternate con.- tact and left-hand armature of relay 203, winding of relay 213 to battery and ground. Relay 213 becomes energized and locks in a circuit from ground, the outer right-hand armature and front contact of relay 200, the inner left-hand armature and back contact of relay 21s, the front contact and left-hand armature of relay 213, winding of relay 213 to battery and ground. After a short interval relay 203 becomes deenergized whereu n a circuit is established from ground, outer right-hand armature and front contact of relay 200, normal contact of the lefthand armature of relay 203, front contact and outer right-hand armature of relay 213, winding ofrelay 204 to battery and ground. Relay- 204 becomes energized and locks in a circuit from ground outer left-hand armature and front contact of relay 204, front contact and outer right-hand armature of relay 21-3, winding of relay 204 to battery and ground. At the same time the ground is removed from the windhlgs of relays T208 and 209- so that these relays now become d'eenergized. It will be noted that "the ing of relay 203 is now extended through the inner left-hand armature and front contact of relay 204 to the winding of stepp='- magnet 21 5, so that upon the-receipt of the next series of impulses the stepping magnet will be energized to move the brushes of the connector switch lorward. It will further be noted that the switch has not been moved in response to the first digit.

hen the first digit is 2. the line relay 201 will be dc-energized twice. in qi'iick succession. Upon the first dee'nergization relays 208 and 209 will become energized in the manner hereinbefore described. Upon the. second deenergization of relay 201 ground will be extended over the outer right-hand arlna-tures and back contacts of relays 205, 206 and 20 7 and thence over the right-hand armature and front contact of relay 208 to the winding of relay 210. Upon the followil'ig energization of relay 201 a circuit will beestablishe'd from "ground, outer righthand "armature and front contact of relay 200, inner left-hand armature and back contact of relay Q/ld, outer left-hand armature and back contact of relay 206, armature and front contact of relay 210, Winding of relay 207, winding of relay 210 to battery and ground, whereupon relay 207 will become energized in series with relay Q10 and relays 208 and will be 'deenergized. During the energization of relay 203 relay 213 becomes energized inthe manner hereinbefore described and upon the d'eenergization of relay 203, relay 204: becomes "energized in the manner hereinbefore described.

In addition to this a circuit will now be established from ground, normal contact 'of the right-hand armature "of relay 203, the innerleft-hand armature and front contact of relay 207, baclr Contact and armature of relay 216, back contact and armature of magnet 215, winding of magnet 21-5 to battery and ground. llla gne't 215 is now included in aself-interinpting circuit and will, consequently, move the brushes of the connector switch step by step until relay 216 is energized to open the circuit just described. Relay 216 will be energized in a circuit from ground, normal contacts of the right-hand armature of relay 203, lnnerlefthand armature and front contact of relay 207, outer left-hand armature and back contact of relay 214, front contact and inner right-hand armature of relay 213, normal contacts "of the innermost right-hand armat-ure of relay '217, brush *CS and its contact corresponding to the secondary normal posi- -relays 206 and 211 will be energizeda-nd the two sets of counting relays corresponding to digits 1 and 2 will-become deenergiz-ed. Relays 213 and 204: will be energized in the manner previously described.

In addition to this 'a circuit will be established from ground, the normal contacts of the right-hand armature of relay 203, the inner left-hand armature and front contact of relay 206, winding of relay 217 to battery and ground. Relay 217 looks up in a circuit from ground, the-outer left-hand armature and front contact of relay 200, left-hand armature and front contact of relay 217, winding of relay 217 to battery and ground. Thus the brushes of the connector switch will, be left in their primary normal position but the relay '217 will become energized to render the brushes GT CR and CS effective.

Vhen the first digit is 4 the brushes will be moved to their second manual position and the relay 217 will become energized thereby rendering the brushes GT CR and CS efi'ec'tive from their second normal position.

Let us now assume that the first dig-it was 2 and that following the movement of the brushes to their second normal position in the manner hereinbefore described, the calling subscriber now sends a series of three impulses. Relay 201 will now become deenergized three times quickly in succession. Upon each'cleenergization of relay *2/01 a circuit is established from battery and back contact of relay 201, front contact and righthand armature of relay 202, winding of relay 203, inner left-hand armature and front contact of relay 204E, winding of magnet 215 to battery and ground. Each deenergization of relay 201 causes the ene-rgiz-ation of magnet 215 so that the brushes are stepped forward three steps from their second nor malposition and come to rest on the term-i nals of line'218 which will be. according to the nuniberi-ng scheme just described, station No. 23. Upon the ener-gization of slowreleasing relay '203 during the sending of the second digit a circuit is established from ground, alternate contacts of the right-hand armature of relay 203, right-hand armature and front contact of relay 204, winding of relay 214 to battery and ground, whereupon relay 2 14 becomes energized. As the brush CS comes to rest 'on the terminals of the called line and relay 203 becomes deenergized, relay 213 becomes deenergi'zed and a circuit is established from the sleeve lit conductor of the called line, through the brush CS, the normal contacts of the inner most right-hand armature of relay 217, the inner right-hand armature and back contact of relay 213, inner right-hand armature and front contact of relay 214, lefthand winding of relay 219 to battery and ground. If the called line is busy ground will be found on the sleeve conductor and relay 219 will become energized, locking up through its righthand winding its front contact and inner left-hand armature to the ground at the front contact and outer right hand armature of relay 200, whereupon busy tone will be extended from the source of busy tone 220, through the front contact and left-hand armature of relay 219, condenser 221, the right-hand winding of impedance coil 222 to battery and ground, whence by induction the busy tone is transmitted to the calling line.

If, on the other hand, the called line is idle, then the battery connection from the cut-off relay 223 is opposed to the battery connection to relay 219 and this relay does not momentarily become energized. Short- 1y, thereafter, relay 214 becomes deenergized whereupon a circuit is establ shed from ground, back contact and innerrighthand armature of relay 214, back contact and inner right-hand armature of relay 213, normal contacts of the innermost righthand armature of relay 217, brush CS, winding of relay 223 to battery and ground so that the called line is now made busy.

During the energization of relay 214, a circuit is established from ground, outermost right-hand armature and front contact of relay 200, innermost left-hand armature and front contact of relay 214, right-hand winding of ringing relay 224 to battery and ground. This relay locks up 1n a circuit from ground, the outermost rlght-hand armature and front contact of relay 200, the innermost right-hand armature and back contact of relay 219, the back contact and armature of relay 225, tl'1e front contact and right-hand armature of relay 224, left-hand winding of relay 224 to battery and ground. Now upon the deenergization of relay 214 a circuit is established from ground off normal contact 226, inner right-hand armature and front contact of relay 200, upper right-hand armature and back contact of relay 214, winding of relay 227 to battery and ground. Through the energization of relay 227 a circuit is established from the source of ringing current 228, Winding of relay 225, front contact and inner left-hand armature of relay 224, front contact and right-hand armature of relay 227, middle right-hand armature and back contact of relay 217, brush CR, and thence over the loop of the called substation, brush CT, backcontact and outermost right-hand armature of relay 217, frontcontact and left-hand armature of relay 227, outer left-hand armature and front contact of relay 224 to ground so that the bell of the called substation is rung. During the ringing of the called substation a small amount of ringing current is shunted over a path from the right-hand armature of relay 227, back contact and lefthand armature of relay 219, condenser 221,

wright-hand winding of impedance coil 222 to battery and ground, whence by induction a ringing tone is transmitted to the calling substation. The current flowing in the ring ing circuit is insufficient to cause theenergization of relay 225 until the called subscriber removes his receiver from the hook, whereupon the flow of current is increased to the point where relay 225 attracts its armature, thereupon opening the locking circuit of relay 224 and cut-ting off the ringing current, at the same time, establishinga direct talking connection between the two subscriber s. V

At the end of the conversation the calling subscriber at substation 100 replaces his receiver on its hook, whereupon the relay 201 becomes deenergized. In a short interval relay 202 becomes deenergized and causes the deenergization of relay 200. This relay removes the ground which is holding relay 107 energized whereupon this relay retracts its armatures. A circuit is also established from ground, the inner left-hand armature and back contact of relay 200, ofl"- normal contact 109, back contact and armature of magnet 108, winding of magnet 103 to battery and ground. Thi'smagnet being now in a self-interrupting circuit moves the brushes of the finder switch to their normal position, whereupon the off-normal contact 109 breaks the circuit of magnet 108 and the finder switch comes to rest. At the same time a circuit is established from ground, off-normal contact 226, the inner right-hand armature and back contact of relay 200, the

back contact and armature-of magnet 215, winding of magnet 215 to battery and ground. Magnet 215 being in a self-interruping circuit moves the brushes of the connector switch to their primary normal position, whereupon the off-normal device 220 breaks the c1rcu1t of magnet 215 and the connector switch comes to normal position.

of counting relays individual to said switch for selecting a particular set of brushes and a particular group of line terminals and means for thereafter directly controlling said switch to make an individual line selection.

3. In a telephone system, a switch having a primary and a secondary normal position and a plurality of sets of brushes, a plurality of relays individual to said switch for selecting a particular set of brushes and causing said switch to move to its secondary normal position and means for thereafter directively controlling said switch to make an individual line selection.

4. In a telephone system, a switch having a primary and a secondary normal position physically separated by groups of line terminal positions and a plurality of sets of brushes, lines connected to terminals at all other positions of said switch, said lines being divided into groups defined by said normal positions and said different sets of brushes, means for making a group selection and means for directively moving saidv switch to make an individual line selection. In witness whereof, I hereunto subscribe my name this 23 day of August A. D,, 1923.

WALTER P. ALBERT. 

